Snap action device



Oct. 24, 1967 s. TAYLOR 3,349,205 SNAP ACTION DEVICE Filed April 2e,1965 2 sheets-sheet 1 I Tacrli0 50 TaqELaX Oct. 24, 1967 s. TAYLOR SNAPACTION DEVICE 2 Sheets-Sheet 2 Filed April 26, 1965 I Illll Tlql.

yflzl INVENTOR ,S/DNEY 72x40? United States Patent C) if 3,349,205 SNAPACTION DEVICE Sidney Taylor, Menlo Park, N.J., assignor to WagnerElectric Corporation, a corporation of Delaware Filed Apr. 26, 1965,Ser. No. 450,996 9 Claims. (Cl. 200-122) This invention relates to animproved vane type snap action device and more particularly to animproved flasher particularly adapted for control of automobile signallamps. The new device is relatively insensitive to load change and hasexcellent voltage response.

There have been many unsuccessful attempts, prior to applicantsinvention, to solve the problem of constructing a flasher which isindependent of load, maintains a sufficient speed of make and breakduring switching to insure little or no arcing between the contacts andhas a low figure of merit. The figure of merit, in a series type flasheris the ratio of the on period of the flasher at eleven volts to the onperiod of the flasher at fifteen volts. In a shunt type flasher, thefigure of merit is the ratio of the off period of the flasher, that is,when the current through the lamps is insuflicient to light the lamps,at eleven volts, to the off period of the flasher at fifteen volts. Aperfect voltage response would be where the figure of merit (F.M.) isone. However, a device which vhas an F.M. of no greater than three isacceptable to automobile manufacturers.

Applicants flasher satisfies all of the above requirements. Prior artflashers which were independent of load had limited life because ofarcing between the contacts and flashers which had sufficient speed andforce to prevent arcing did not function properly at different loads.

Applicants invention provides a snap action device which has a lowfigure of merit, no detectable arcing between the contacts, will notdrift from set tolerances after being in use for long periods of timeand which can be made to operate independent of load.

As in prior art devices, for example that of Schmidinger Reisue Patent24,023, applicants device comprises a vane of thin resilient materialand of any desired shape which has a deformation therein tending tocause the vane to curve or bend about one axis, and an expansible pullelement which is connected at its ends under tension to the vane andwhich when cold holds the vane in a bowed or buckled position in whichit is curved about one axis 90 from the axis of the deformation. In theprior art devices, the initial or inherent deformation has generallybeen introduced by bending the vane over a mandrel or by formingcontinuous or discontinuous ribs therein along one axis. Thedeformations in such prior art vanes caused the vane, before the ribbonwas attached, to have a generally uniform curvature about the axis ofdeformation.

As distinguished from these prior art vanes, applicants novel vane is sodeformed that the curvature of the vane introduced by the deformation ismaximum adjacent the periphery and minimum in the central area of thevane. This change in initial deformation results in the superioroperation of applicants device.

The initial deformation yielding the above described variations incurvature can be introduced by providing ribs on the vane which taper,either in depth or in width,

from a maximum adjacent the periphery to a minimum in the central area.

The new vane is assembled to the flasher by first bowing or buckling thevane about an axis at right angles to the deformation formed by the ribsand then attaching a pull ribbon or wire to the sides of the vane tohold the vane in the buckled position.

The assembly of vane and ribbon is supported by a bracket attachedeither to the vane or to the ribbon. The

' position and the ribbon starts to 3,349,205 Patented Oct. 24, 1967movable contact may be mounted either on the ribbon or on the vane. Whenthe flasher is arranged for series operation, the contact is mounted onthe vane if the support is attached to the ribbon and conversely if thesupport is attached to the vane, the contact is mounted on the ribbon.When the flasher is arranged for shunt operation, both the support andthe movable contact may be mounted on the vane.

When the ribbon is heated, either by current flowing directly through itor by a heating coil, the ribbon will expand and the vane which is heldin the buckled or constrained position by the ribbon will snap andreturn toward the position to which it is biased by the ribs. Thistendency of the vane to oppose the tension of the pull ribbon andconstantly seek to return to the position to which it is biased by theribs is characteristic of the monostable type of vane to which thisinvention relates.

The reason for the improved operation of a flasher constructed withapplicants unique vane is not completely understood. It is believedhowever, that by tapering the ribs, the end areas of the vane becomemore rigid than the central portion of the vane. This prevents the endareas of the vane from bending as a result of the contraction of theribbon before the central portion of the vane starts to move. The forcegenerated by the contacting ribbon will first be directed to the weakercentral portion of the vane causing the vane to move with suflicientspeed and force to prevent arcing at the contacts. Further, the forcenecessary to buckle the vane is smaller than would normally be requiredsince there is no waste of the force generated by the ribbon in bendingthe ends of the vane. Therefore, less heat is required at the ribbonresulting in lower current devices insensitive to load changes.

This theory also applies when the vane is in the buckled expand. Theenergy stored by the vane will be directed to the weaker central area ofthe vane because of the tapered ribs resulting in the necessary speed ofbreak to prevent arcing at the contacts.

Although applicants novel vane construction is adapted for use both inseries type and shunt type devices, the presently preferred use of thevane is in a shunt type flasher utilizing a heater winding about thepull ribbon. In such type flasher, the contacts are normally open andwhen the circuit is closed, current flows through the heater to theload, the resistance of the heater being high enough to preventillumination of the lamps when the load is a lamp load. The currentthrough the heater heats the pull ribbon, causing it to expand andpermit the vane to snap toward the position to which it is biased by theribs. In this position, the contacts are closed and the heater isshunted. The full voltage is thereupon supplied to the lamps and theylight. The pull ribbon thereupon cools and contracts and snaps the vaneback into the contact open position. Applicants novel vane, when used inthis type flasher, insures the desired speed of make and break of thecontacts and reduces the amount of heat necessary for snapping the vane.

In applicants shunt type flasher, as above briefly described, the pullribbon is attached at its ends to opposite edges of the vane andembossed platforms are formed in the vane adjacent the points ofattachment of the ribbon to the vane. The platforms insure clearance forthe heater winding when the ribbon is cold, allowing the heater to touchthe vane in the area between the platforms when the ribbon is hot. Thisarrangement improves the figure of merit of the device.

vane insures rapid cooling of the pull ribbon by the relatively coolervane, resulting in the vane returning quickly to the position wherein itis buckled about an axis 90 to the deformation introduced by the ribs.This permits operation at a lower average temperature and improves thefigure of merit.

For a better understanding of the invention and of the advantagesthereof, reference may be had to the accompanying drawings whichillustrate preferred embodiments of the invention.

FIG. 1 is a plan view of a vane formed with ribs tapering in height.

FIG. 2 is a sectional view taken along line 22 of FIG. 1.

FIG. 3 is a plan view of a vane formed with a rib tapering in width.

FIG. 4 is a sectional view taken along line 4-4 of FIG. 3.

FIG. 5 is a plan view of a vane formed with interrupted ribs tapering inheight and showing a ribbon mounted on and overlying the convex side ofthe deformation introduced by the ribs.

FIG. 6 is a sectional view taken along line 6--6 of FIG. 5.

FIG. 7 is a top perspective view of a vane formed with interrupted ribstapering in width and showing a ribbon mounted on the vane and overlyingthe convex side of the deformation formed by the ribs.

FIG. 8 is a sectional view taken along lines 88 of FIG. 7.

FIG. 9 is a front view of a shunt type flasher incorporating a vane ofthe type of FIG. 1.

FIG. 10 is a rear view of the shunt type flasher of FIG. 9.

FIGS. 11 and 12 are exaggerated diagrammatic views showing the shunttype flasher in the off and on position, respectively.

FIG. 13 is a front view of a series type flasher incorporating a vanesimilar to the vane of FIG. 2.

FIG. 14 is a rear view of the series type flasher of FIG. 13; and

FIGS. 15 and 16 are exaggerated diagrammatic views of the series typeflasher in the on and off position, respectively.

FIGS. 1 through 8 inclusive show various arrangements and constructionsof the vane of the invention.

Referring to FIGS. 1 and 2, a rectangular vane of a suitable resilientelectrically conducting material such :as spring steel is formed withtapering ribs 32 and with two small holes 34 symmetrically placed withrespect to the short axis and lying along the long axis of the vane.Although the vane is shown in rectangular form, it is to be understoodthat any other configuration may be used without affecting the operationor merits of the The ribs are formed higher at the sides 36 of the vaneand then gradually taper to a minimum height at the holes 34. The degreeof taper will depend on the thickness of the vane, the material used tomake the vane, and the operating current of the device in which the vaneis used.

For flashers for twelve volt automobile circuits, a vane of one inch byone-half inch of spring steel with ribs tapering from a height of fouror five and a half thousandths of an inch to three or three and a halfthousandths ofan inch is recommended although other combinations of ribheight and vane dimension can be employed.

Although the provision of the two holes 34 is not essential as a singlelarger hole could be provided or the center of the vane could beimperforate, there are certain advantages in the provision of the twoholes. In

mass production, termination of a rib at a hole simplifies the toolsrequired in the stamping operation. Also the two holes increase theweakening of the vane in the central area which, as heretoforedescribed, is advantageous in insuring rapid make and break. However,depending upon where a contact is to be mounted, it is advisable not tohave the central section of the vane too weak. In a preferred embodimentof the flasher as will be described in connection with FIGS. 9 and 10,the movable contact is secured adjacent the longer side of the vane andin the central area of such longer side. The area of the vaneintermediate the two holes provides the required strength in the centralarea to which the contact in the preferred embodiment is secured. Afurther advantage of the two-hole construction is that it permits theproduction machines to use aligning pins during the manufacturingprocess.

FIGS. 3 and 4 show a square shaped vane 38 provided with ribs 40 whichare of uniform depth but are wider at the ends 42 of the vane 38 andtaper to a minimum width at a central hole 44. Preferably, the width ofeach rib 40 at the outer end thereof is about one quarter or one thirdof the width of the vane and at the inner end is about one tenth of thewidth of the vane but wider or narrower ribs could be employed.

It will be noted that in the embodiment of FIGS. 3 and 4 there is onlyone hole 44 but two holes could be provided if desired.

FIGS. 5 and 6 show a circular vane 52 in which four ribs 54 having atapered height are symmetrically place-d about one diameter of the vaneso as to form a deformation along the said diameter. In thisarrangement, the ribs are formed as in FIG. 1 but terminate short of theperiphery of the vane. The height of each rib 54 is maximum at its outerend and gradually tapers to a minimum in the central portion of thevane. A ribbon 56 is attached at its ends under tension to the peripheryof the vane 52 and overlies the convex side of the deformation formed bythe ribs and when cold holds the vane in buckled position, that is,bowed about an axis 90 to the axis of the deformation.

FIGS. 7 and 8 show an oval shaped vane 58 in which four ribs 60 areformed therein so as to form a permanent deformation along the minordiameter of the vane. The ribs are concave as viewed in FIG. 7, are ofuniform depth but wider nearer the periphery of the vane, and taper to azero width adjacent the central region of the vane. The ribs 60 are thetype shown in FIGS. 2 and 3 except they do not extend to the edge of thevane or terminate at an opening in the vane. A ribbon 62 is attached atits ends to the periphery of the vane and overlies the minor diameter ofthe vane on the convex side of the deformation formed by the ribs.

In FIGS. 9 and 10, a shunt type flasher is shown having a vane of thetype of FIG. 1. The vane 62 formed with ribs 64 of tapering depth issupported by a post 66 which is welded at 68 to the vane adjacent thecenter of a longer side thereof. The vane is formed with two embossedplatforms 70 at opposite ends of a diagonal. A ribbon 72 overlies theplatforms 70 and is attached at its ends to the corners of the vane. Theribbon overlies the vane on the convex side of the deformation caused bythe ribs and when cold holds the vane bowed about an axis 90 to thedirection of the ribs.

An insulated heating coil 74 is wound around the ribbon and fastened atone end to the ribbon or vane and at the other end to a post 76 whichholds a stationary contact 77. It is important to use an insulation forthe coil which will not make the wire so stiff that it is difficult towind, will not be so brittle as to break, or so weak that it does notgive suflicient insulation. Further, the insulation must be able towithstand constant heating and cooling without deteriorating. Also theinsulation preferably should have high heat conductivity and lowelectrical conductivity. Applicant has found that a suitable insulationmaterial for use on the coil is made from a polymer of amide-imide. TheA-rnoco Co. sells this par ticular insulation under the service markA1420.

deformation formed by the ribs, opening the 5 The embossed plat forins70 will prevent the coil 74 from contacting the 'vane when the vane isin the buckled position. However, the platforms 70 will not prevent theEoil from contacting the vane between the platforms when the ribbon hasexpanded and the vane has snapped toward the position to which it isbiased by the deformation. The coil being in contact with a largercooler body will give up its heat rapidly, allowing the vane to returnquickly to the buckled position. As explained before, rapid coolingimproves the figure of merit. In the buckled position, when the coil isout of contact with the vane, most of the heat generated by the coilwill be con-ducted to the ribbon. This increases the sensitivity of theflasher since a smaller current can be used for heating the coil.

A contact 78 is mounted on the vane 62 at a position where it will meetstationary contact 77 when the ribbon is hot. The post 66'which supportsthe vane 62 and the second post 76 on whichthe contact 77 is mounted ismolded into a plastic base 80 by conventional methods.

When the flasher is arranged in a conventional automobile circuit,closure of thedirectional switch causes current to flow from the batterythrough post 66, vane 62, coil 74""and second' post 76. In FIGS. 11 and12 the battery connection is indicated at X and the load connection atL. As current passes through the coil, it heats the coil which in turnheats the ribbon until the ribbon expands suificiently to allow the vaneto snap to contact closing position. (See FIG. 12.) When the contactsare closed, current flows from the battery through post 66, vane 62,contact 78 mounted on the vane, contact 77 carried by post 66 and post76. No current will flow through the ribbon or coil since the vane,which has virtually no resistance, will short the ribbon and coilallowing the ribbon and coil to cool. When the ribbon cools andcontracts sufficiently, it snaps the vane at a 90 angle to the contacts77 and 78. The alternate opening and closing of the contacts willcontinue as long as the directional switch is closed. The load ordirectional lamps of the automobile are arranged in relation to theflasher so that when the contacts are closed, the lamps are on, and whenthe contacts are open, there is insufficient current to cause the lampsto light.

A series type flasher is shown in FIGS. 13 and 14 incorporating a vanesimilar to the vane of FIG. 3. The vane 82 has a pair of ribs 84 ofuniform depth and whose width are greatest at the ends 90 of the vaneand are tapered to a point short of the center 92. of the vane. The ribsare concave as viewed in FIG. 13. A ribbon 94 is attached at its ends tothe sides of the vane and extends parallel to the ribs. Theribbon isattached while the vane is bowed about an axis 90 to the longitudinalaxis.

A post 96 is attached to the ribbon at 98 and supports the ribbon andvane. A second post 100 carries a fixed contact 102 which will meet witha contact 104 carried by the vane 82 when the pull ribbon is cold.

The series type flasher is arranged in the conventional automobilecircuit so that when the directional switch is closed, current from thebattery flows through post 96, ribbon 94, vane 82, contact 104 carriedby the vane and contact 102 mounted on post 96 and post 100 (see FIG.The current is suflicient to heat the ribbon to the point where itsexpansion permits the vane to snap toward the position to which it isbiased by the deformation introduced by the ribs 84, opening contacts102 and 104. When the contacts are open, no current flows through thevane or the ribbon and the ribbon will cool. With the cooling andattendant contraction of the ribbon, the vane will snap back intocontact closing position. As with the shunt type flasher, the alternateopening and closing of the contacts, with the attendant turning off andon of the signal lamps, will continue as long as the directional switchis closed.

The invention has now been described with reference to variousembodiments thereof. Although in each case 6 reference has been made tothe snap action device of the invention as being a flasher for use incontrol of automobile directional signals, obviously the device may beemployed for intermittently energizing any load or could be employed asa re-closing circuit breaker. In each embodiment of the inventionillustrated in the drawings, ribs have been illustrated of taperingwidth or thickness for providing the inherent deformation in the vane.In all embodiments of the invention, the ribbon has been described asoverlying the convex side of the inherent deformation occasioned by theribs. In all figures, except FIGS. 7 and 13, the ribs are convex on theside of the vane over which the pull ribbon extends whereas in FIGS. 7and 13 the ribs are described as concave toward the ribbon. It will beappreciated by those skilled in the art that the curvature introduced bythe ribs depends not upon the direction in which the metal of the ribsis displaced from the surface of the vane but upon the configuration ofthe lips of the forming tools used to impress the ribs upon the vane. Inother words, the inherent curvature introduced into the vane by the ribsdepends upon the tool used in impressing the ribs on the vane and notupon the direction in which the metal of the vane is displaced. I

Various changes in the specific constructions illustrated in thedrawings can be made without departing from the spirit of the inventionor the scope of the accompanying claims. For example, only in FIGS. 1and 9 have two central holes been shown in the vane. Obviously two holescould be employed in the constructions illustrated in the other figuresof the drawings or conversely the embodiments of the inventionillustrated in FIGS. 1 and 9 could be provided with a single hole at thecentral region or with no holes. The same is true of the embodiments ofthe invention illustrated in FIGS. 5, 7 and 13. Also, although the ribshave been shown and described as tapering either in height or in width,obviously ribs tapering both in height and in width could be employed.Other variations will occur to those skilled in the art.

I claim:

1. In a snap action device for control of directional signals ofautomotive vehicles of the type wherein a deformed vane of resilientconducting material snaps back and forth between circuit controllingpositions to interrupt the flow of current to the automobile signallamps in response to expansion and contraction of a pull ribbon securedat spaced points to the vane, the improvement which comprises at leastone rib formed in the vane the said rib being concave relative to onesurface of the vane and convex relative to the second opposite surfaceof the vane and tapering in at least one dimension from a maximumadjacent the periphery of the vane to a minimum adjacent the centralportion of the vane to provide a deformation in the vane along one axiswhich biases the vane to make it monostable and thereby cause it alwaysto seek and assume one circuit controlling position when the pull ribbonexpands, said vane snapping to a second circuit controlling position inwhich the vane is curved along an axis angularly disposed to said firstaxis and at opposite curvature to said first deformation when the ribboncontracts.

2. The improvement according to claim 1 wherein said rib tapers inheight from points adjacent the periphery of the vane to the centralarea.

3. The improvement according to claim 1 wherein the rib tapers in widthfrom points adjacent the periphery of the vane to the central area.

4. The improvement according to claim 1 wherein the vane is providedwith two aligned ribs which terminate adjacent the central area of thevane and the vane is apertured at each such termination.

5. A vane type flasher for control of directional signals of automotivevehicles comprising a vane having a deformation therein tending to bowthe vane about one axis, said deformation comprising a rib which isconcave relative to one surface of the vane and convex relative to thesecond opposite surface of the vane having a maximum dimension adjacentopposite portions of the periphery of the vane and a minimum dimensionin the central area of the vane, the said deformation being effective toprovide a bias in the vane which makes it monostable whereby it alwaysseeks to return toward the position of the said deformation, a heatexpansible pull means secured at its ends to parts of said vane adjacentthe periphery and overlying the surface of the vane which is made convexby the deformation, said pull means when cold bowing the vane about anaxis an-gularly disposed to said one axis and when heated permitting thevane to snap to opposite curvature about said one axis toward theposition given to the vane by the said deformation, and means forintermittently heating said pull means.

6. The flasher according to claim 5 wherein said vane is rectangular,said rib extends parallel to one side and is of varying height.

7. The flasher according to claim 6 wherein the central area of saidvane is provided with two spaced apertures, said rib being interruptedby said apertures and by the vane surface therebetween.

8. The flasher according to claim 6 wherein said vane is provided withraised platforms adjacent two diagonally opposite corners, the pullmeans passingover and enga ing said platforms, and wherein said meansfor intermittently heating said pull means includes an electricallyinsulated heater coil wound about said pull means, said platformsspacing said heater coil from the vane surface when the vane is bowedunder the tension in the pull meansand permitting the heater coil toengage the vane surface for rapid cooling when the-pull means expandsand the vane snaps :to pposite curvature.

9. The flasher according to claim 8 wherein the heater wire iselectrically insulated by a composition having high electricalresistance and high thermal conductivity.

References Cited UNITED STATES PATENTS 1,895,590 1/ 1933 Spencer 200 138X 1,895,591 1/1933 Spencer. 1,988,345 1/1935 Vaughn. 2,299,562 10/ 1942Burch. 200113 X 2,615,106 10/ 1952 Schmidinger. 3,174,013 3/ 1965Siiberg 210M122 3,218,415 11/1965 Voorman 200-113 X BERNARD A. GILHEANY,Primary Examiner.

H. A. LEWI'ITER, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,349,205 October 24, 1967 Sidney Taylor It is hereby certified thaterror appears in the above numbered patent requiring correction and thatthe said Letters Patent should read as corrected below.

Column 5, line 61, for "96" read 100 column 8, after line 22, insert3,174,015 3/1965 Almassy Signed and sealed this 12th day of November1968.

(SEAL) Attest:

EDWARD J. BRENNER Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer

1. IN A SNAP ACTION DEVICE FOR CONTROL OF DIRECTIONAL SIGNALS OFAUTOMOTIVE VEHICLES OF THE TYPE WHEREIN A DEFORMED VANE OF RESILIENTCONDUCTING MATERIAL SNAPS BACK AND FORTH BETWEEN CIRCUITS CONTROLLINGPOSITIONS TO INTERRUPT THE FLOW OF CURRENT TO THE AUTOMOBILE SIGNALLAMPS IN RESPONSE TO EXPANSION AND CONTRACTION OF A PULL RIBBON SECUREDAT SPACED POINTS TO THE VANE, THE IMPROVEMENT WHICH COMPRISES AT LEASTONE RIB FORMED IN THE VANE THE SAID RIB BEING CONCAVE RELATIVE TO ONESURFACE OF THE VANE AND CONVEX RELATIVE TO THE SECOND OPPOSITE SURFACEOF THE VANE AND TAPERING IN AT LEAST ONE DIMENSION FROM A MAXIMUMADJACENT THE PERIPHERY OF THE VANE TO A MINIMUM ADJACENT THE CENTRALPORTION OF THE VANE TO PROVIDE A DEFORMATION IN THE VANE ALONG ONE AXISWHICH BIASES THE VANE TO MAKE IT MONOSTABLE AND THEREBY CAUSE IT ALWAYSTO SEEK AND ASSUME ONE CIRCUIT CONTROLLING POSITION WHEN THE PULL RIBBONEXPANDS, SAID VANE SNAPPING TO A SECOND CIRCUIT CONTROLLING POSITION INWHICH THE VANE IS CURVED ALONG AN AXIS ANGULARLY DISPOSED TO SAID FIRSTAND AT OPPOSITE CURVATURE TO SAID FIRST DEFORMATION WHEN THE RIBBONCONTRACTS.